In the past few years computers and electronic imaging has created the opportunity for individuals at home and work to design colored graphics and print such images in ink jet, electrographic, wax thermal transfer, dye diffusion thermal transfer and electrophotographic printers. The print media substrate for each printing system is tailored to meet basic imaging requirements. When imaged materials are intended for outdoor exposure, additional processing steps are necessary to make images robust enough to withstand the adverse conditions associated with indoor/outdoor use. Examples of these additional process steps include laminating plastic films over the printed image, or over-printing the printed image with a clear protective covering such as varnish or the like.
Ink jet, laser and electrographic transfer papers are subject to a multiplicity of manufacturing steps and specialized transfer equipment. Even so, they still may require over laminating with plastic film because the release coating is necessarily soft to accommodate the transfer step operation.
Imaging media for digital ink jet printing is divided into three primary groups. These groups are typically differentiated based on the particular substrate employed in the printing operation, i.e., paper or film or fabric. Each substrate primary group can be further distinguished based on parameters such as its relative thickness and surface texture (ranging from glossy to matte for paper and film). The gross topography of certain surfaces such as fabric and canvas substrates, for example, add additional product distinctions.
Commercial providers of graphic media therefore must carry extensive inventories of various imaging media and laminating films to meet the range of requisite customers needs. Furthermore, most all of the above-described imaging media is very susceptible to damage from smearing, water, scratching and may be tacky to the touch. Even crosslinked vinyl films are easily scratched when wet.
Lamination of printed material is generally performed by post-laminating techniques subsequent to the formation of the subject printed material. This mode of operation is time consuming and expensive. Problems with the post-lamination process which also result include wrinkling, curl, delamination, bubbles and other defects which then requires additional printing and laminating steps to be performed.
The aforementioned problems which are present in prior art imaging media; and in methods for producing such imaging media, have been overcome by the scratch-resistant laminated printed materials of the present invention, and by the methods for producing such materials.
It is therefore an object of this invention to provide such printed materials having a robust image that is produced by a unique method which reduces overall image cost by eliminating a subsequent over laminate film step.
It is a further object of this invention to provide a unique method for producing the subject printed materials that are substantially scratch resistant.
It is a further object of this invention to provide a unique method for producing the subject printed materials that are water, oil and solvent resistant, without requiring the use of additional consumable laminating materials.
It is a further object of this invention to provide a unique method for producing the subject printed materials that can be printed in both large and small format ink jet printers.
It is a further object of this invention to provide a unique method for producing the subject printed materials which can be printed employing solvent coating systems.
It is a further object of this invention to provide a unique method for producing the subject printed materials which are bonded to foil, paper photographs and substantially all porous substrates.
It is a further object of this invention to provide a unique method for producing the subject printed materials that are capable of receiving handwritten indicia using common writing instruments.
It is a further object of this invention to provide a unique method for the subject printed materials that maintain the security of the image.
It is a further object of this invention to provide a unique method for producing the subject printed materials having various outer surface patterns and textures.
It is a further object of this invention to provide a unique method for producing the subject printed materials having a plurality of thicknesses depending on the particular end use.
It is a further object of this invention to provide a unique method for producing the subject printed materials on paper substrates with enhanced wet strength properties.
These and other objects and advantages result in a preferred method which permits the formation of an imaging media capable of accepting substantially all conventional printing techniques and yet so that it can be used either in the home or by commercial print houses in conjunction with existing printing equipment.
More specifically, a method for producing a unique scratch-resistant, self-laminated printed material is provided. The subject method comprises providing a first underlying substrate layer having at least one major surface which is capable of being transported through a printing device. Preferably, the first layer is selected from a group consisting of paper, a polymer film, and a nonwoven polymer fabric.
Next, a second layer is formed having at least one major surface. This second layer is formed on at least one of the major surfaces of the first layer. The second layer is flowable when heated to at least it""s melting point and is fusible below its melting point. Preferably, the second layer comprises a thermoplastic polymer. The second layer preferably has a melting point from about 70 to 80xc2x0 C.
A third layer is then formed on at least one of the major surfaces of the second layer. At least one of the major surfaces of the third layer is printable. The third layer is substantially permeable, so that when the second layer is in a flowable state, the second layer will permeate through and about the third layer.
The third layer preferably comprises a solvent-based material. Typically, the third material comprises a thermoplastic binder, an inorganic pigment, and a cationic polymer. In the case where a cationic polymer is employed, it preferably comprises a polyquartemary amine.
The thermoplastic binder generally serves as a binding resin for the inorganic pigment. The thermoplastic binder preferably is present in an amount from about 20 to 60 weight percent, more preferably from about 30 to 45 weight percent, and most preferably from about 35 to 50 weight percent, based on the total third layer weight. The thermoplastic binder is preferably a nylon multi-polymer resin. The thermoplastic binder preferably has a melting point from about 100 to 175xc2x0 C., more preferably a melting point from about 105 to 170xc2x0 C., and most preferably a melting point from about 110 to 165xc2x0 C. Preferably, the difference in the melting point temperatures between the respective second and third layers is about 25xc2x0 C., more preferably about 50xc2x0 C., and most preferably about 75xc2x0 C.
The material also contains a inorganic pigment which is present in an amount of from about 30 to 80 weight percent, more preferably from about 35 to 70 weight percent, and most preferably from about 30 to 60 weight percent, based on total layer weight. Moreover, the inorganic pigment has a particle size of up to about 25 microns, more preferably up to about 20 microns, and most preferably up to about 15 microns in particle size. In the most preferred case, the inorganic pigment is a mineral pigment. The mineral pigment can be metal-based particulate filler material such as a Si-based, SiO-based, Ti-based, Ca-based or Mg-based filler material. In another preferred form, the inorganic pigment is treated with a wetting agent to facilitate dispersion in the third layer.
The printable multi-layer composite structural material formed as described above is capable of having predetermined image printed onto at least one printable major surface of the third layer. Once the predetermined image is printed onto the printable multi-layer composite structural material, the second layer is heated above its melting point until it is in a flowable state. Then, the flowable second layer permeates through and about the third layer and about the predetermined image. Finally, the flowable second layer is fused by lowering its temperature below it""s melting point thereby encapsulating the third layer and the predetermined image and forming the scratch-resistant, self-laminated fused printed material of the present invention.